Memorandum on Colorado River water supply and compact interpretation.

MEMORANDUM ON COLORADO RIVER WATER SUPPLY
AND COMPACT INTERPRETATION.
The attached chart entitled "Compact Interpretation" graphically represents the water supply available under Arizona's interpretation and under California's interpretation of the Compact. The area shown in red represents the water available for California; the area shown in yellow represents the water available for use in Arizona; the area shown in blue represents the water to be allocated to Nevada; and the area shown in green represents the amount of water used in Mexico prior to the construction of Boulder Dam. This is probably the minimum amount of water that would be given to Mexico in the event that a treaty is made between Mexico and the United States over the waters of the River. In all probability this figure would be exceeded. However, this figure does not represent any established right to the use of water in Mexico. The hatched areas represent the present use of water in Lower Basin at this time; and the stippled areas represent the surplus water contracted for with Secretary of the Interior by California.
The Boulder Canyon Project Act states in part--"an express covenant and in consideration of the passage of this Act, that the aggregate annual consumptive use (diversions less returns to the River) of water of and from the Colorado River for use in the state of California including all uses under contract made under provision of this Act and all water necessary for the supply of any rights which may now exist shall not exceed 4,400,000 acre feet of waters apportioned to the Lower Basin States by paragraph (a) of Article III of the Colorado River Compact plus not more than one-half of any excess or surplus waters unapportioned by said Compact, such uses always to be subject to the terms of said Compact."
Arizona interprets that to mean that California is entitled to 4,400,000 acre feet of the III (a) water. In addition to this, California is entitled to one-half of the surplus over and above the III (a) and III (b) water, this one- half being an equal division of such surplus water between the two States without respect prior appropriation by either State. Under such an interpretation, Arizona would satisfy the rights of the existing uses on the main stream of the Colorado River and such uses as are made of the waters of the Little Colorado River (measured at the mouth), and the uses of the Gila River (measured at the mouth), from Arizona's share of the water allocated to the Lower Basin. Arizona's share to this water being established by deduction. In other words, there are 7,500,000 acre feet of III (a) water allocated to the Lower Basin, of which California would receive 4,400,000 acre feet, Nevada would receive 300,000 acre feet of this water, leaving 2,200,000 acre feet of III (a) water for use in Arizona.
It is Arizona's contention that California, by her Limitation Act, excluded herself from the use of any III (b) water, owing to the fact that III (b) water is not surplus water. Therefore, California has no right to the use of any of ths water. Under this interpretation, Arizona would have a total of 3,800,000 acre feet of III (a) and III (b) water with which to satisfy all of the State's needs, pluse one-half of an undetermined amount of surplus. This amount of water is barely sufficient to satisfy the needs of the existing projects and the Colorado River Indian Project, and the Gila Project, both of which are under construction. Any other projects would, necessarily, look to a rather uncertain water supply from the surplus waters. Under this interpretation, California's contracts with the Secretary of the Interior would be in excess of one-half of the surplus water available to the Lower Basin, and would encroach upon the water claimed by Mexico.California has another interpretation. California agrees that they are limited to 4,400,000 acre feet of the III (a) water, plus one-half of the surplus. But Arizona and California differ considerably over the matter of surplus water. It is California's contention that III (b) water is a part of the surplus water and that they have a right to the first one-half of this water by prior appropriation. Under such an interpretation there would be insufficient water to meet the present perfected rights and the initiated rights to projects which are now under construction.
Reservoir losses have not been mentioned, either in the Colorado River Compact or the Boulder Canyon Act. Whether these losses are to be considered as a normal depletion or to be deducted from the apportionment made to the Lower Basin is something that has never been definitely determined. In the event that these losses were to be deducted from the allocated water, Arizona undoubtedly would stand a share of these deductions, which would further reduce the water available for use in Arizona. Also, if the definition of "consumptive use" as defined in the Bould Canyon Project Act (with respect to California's limitation) is applied t the uses of water on the Gila and the Little Colorado Rivers and not to the water contributed by these Rivers at the mouth, the total uses in Arizona by these Rivers at the mouth, the total uses in Arizona would be, roughly, 4,300,000 acre feet.
Under California's interpretation, we would be allocated 2,800,000 acre feet of III (a) water and a very small and unreliable amount of surplus water which must be used to satisfy Arizona's needs. Deducting the 2,800,000 acre feet from the Arizona use (using the consumptive use theory), would leave, roughly, 1,500,000 acre feet of water being used in the state of Arizona, to be accounted for by a small and undeterminate amount of surplus water. Under such an interpretation it is quite evident that in the final analysis we would end up by owing the Colorado River System water.
The following table is taken from the summary in a report dated December 1934 by Mr. E.B. Debler, of the United States Bureau of Reclamation, entitled "Stream Flow of Lower Colorado River and its Tributaries."
"Colorado River, exclusive of Gila River.
"From a study of stream flow records for the years 1897-1934 inclusive, the flow of the Colorado River at Lees Ferry under virgin conditions with no development, and under future conditions with an average annual depletion of 7,500,000 acre feet by the Upper Basin is presented in the following table. The table also shows the probable amounts available for local use and exportation after allowing for evaporation from the Boulder Canyon reservoir and from the reservoirs that will lie back of the Bridge Canyon, Bullshead and Parker dames, if and when constructed.
[table]
The three following tables, which contain data taken from the various reports on Colorado River matters but mostly from a joint report by Messrs. Jacobs and Stevens, consulting engineers, and a report of R.J. Tipton, consultinhg engineer, entitled, "Report on Colorado River and Allied Matters," are presented to indicate what may become of the 9,500,000 acre-feet given in the foregoing table as the average annual flow past Boulder Dam under ultimate conditions of depletion. These tables are not intended to indicate any conclusions or opinions of the writer. In every case they show the maximum quantities proposed.
[tables]

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Arizona State Library, Archives and Public Records--State Library of Arizona.

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MEMORANDUM ON COLORADO RIVER WATER SUPPLY
AND COMPACT INTERPRETATION.
The attached chart entitled "Compact Interpretation" graphically represents the water supply available under Arizona's interpretation and under California's interpretation of the Compact. The area shown in red represents the water available for California; the area shown in yellow represents the water available for use in Arizona; the area shown in blue represents the water to be allocated to Nevada; and the area shown in green represents the amount of water used in Mexico prior to the construction of Boulder Dam. This is probably the minimum amount of water that would be given to Mexico in the event that a treaty is made between Mexico and the United States over the waters of the River. In all probability this figure would be exceeded. However, this figure does not represent any established right to the use of water in Mexico. The hatched areas represent the present use of water in Lower Basin at this time; and the stippled areas represent the surplus water contracted for with Secretary of the Interior by California.
The Boulder Canyon Project Act states in part--"an express covenant and in consideration of the passage of this Act, that the aggregate annual consumptive use (diversions less returns to the River) of water of and from the Colorado River for use in the state of California including all uses under contract made under provision of this Act and all water necessary for the supply of any rights which may now exist shall not exceed 4,400,000 acre feet of waters apportioned to the Lower Basin States by paragraph (a) of Article III of the Colorado River Compact plus not more than one-half of any excess or surplus waters unapportioned by said Compact, such uses always to be subject to the terms of said Compact."
Arizona interprets that to mean that California is entitled to 4,400,000 acre feet of the III (a) water. In addition to this, California is entitled to one-half of the surplus over and above the III (a) and III (b) water, this one- half being an equal division of such surplus water between the two States without respect prior appropriation by either State. Under such an interpretation, Arizona would satisfy the rights of the existing uses on the main stream of the Colorado River and such uses as are made of the waters of the Little Colorado River (measured at the mouth), and the uses of the Gila River (measured at the mouth), from Arizona's share of the water allocated to the Lower Basin. Arizona's share to this water being established by deduction. In other words, there are 7,500,000 acre feet of III (a) water allocated to the Lower Basin, of which California would receive 4,400,000 acre feet, Nevada would receive 300,000 acre feet of this water, leaving 2,200,000 acre feet of III (a) water for use in Arizona.
It is Arizona's contention that California, by her Limitation Act, excluded herself from the use of any III (b) water, owing to the fact that III (b) water is not surplus water. Therefore, California has no right to the use of any of ths water. Under this interpretation, Arizona would have a total of 3,800,000 acre feet of III (a) and III (b) water with which to satisfy all of the State's needs, pluse one-half of an undetermined amount of surplus. This amount of water is barely sufficient to satisfy the needs of the existing projects and the Colorado River Indian Project, and the Gila Project, both of which are under construction. Any other projects would, necessarily, look to a rather uncertain water supply from the surplus waters. Under this interpretation, California's contracts with the Secretary of the Interior would be in excess of one-half of the surplus water available to the Lower Basin, and would encroach upon the water claimed by Mexico.California has another interpretation. California agrees that they are limited to 4,400,000 acre feet of the III (a) water, plus one-half of the surplus. But Arizona and California differ considerably over the matter of surplus water. It is California's contention that III (b) water is a part of the surplus water and that they have a right to the first one-half of this water by prior appropriation. Under such an interpretation there would be insufficient water to meet the present perfected rights and the initiated rights to projects which are now under construction.
Reservoir losses have not been mentioned, either in the Colorado River Compact or the Boulder Canyon Act. Whether these losses are to be considered as a normal depletion or to be deducted from the apportionment made to the Lower Basin is something that has never been definitely determined. In the event that these losses were to be deducted from the allocated water, Arizona undoubtedly would stand a share of these deductions, which would further reduce the water available for use in Arizona. Also, if the definition of "consumptive use" as defined in the Bould Canyon Project Act (with respect to California's limitation) is applied t the uses of water on the Gila and the Little Colorado Rivers and not to the water contributed by these Rivers at the mouth, the total uses in Arizona by these Rivers at the mouth, the total uses in Arizona would be, roughly, 4,300,000 acre feet.
Under California's interpretation, we would be allocated 2,800,000 acre feet of III (a) water and a very small and unreliable amount of surplus water which must be used to satisfy Arizona's needs. Deducting the 2,800,000 acre feet from the Arizona use (using the consumptive use theory), would leave, roughly, 1,500,000 acre feet of water being used in the state of Arizona, to be accounted for by a small and undeterminate amount of surplus water. Under such an interpretation it is quite evident that in the final analysis we would end up by owing the Colorado River System water.
The following table is taken from the summary in a report dated December 1934 by Mr. E.B. Debler, of the United States Bureau of Reclamation, entitled "Stream Flow of Lower Colorado River and its Tributaries."
"Colorado River, exclusive of Gila River.
"From a study of stream flow records for the years 1897-1934 inclusive, the flow of the Colorado River at Lees Ferry under virgin conditions with no development, and under future conditions with an average annual depletion of 7,500,000 acre feet by the Upper Basin is presented in the following table. The table also shows the probable amounts available for local use and exportation after allowing for evaporation from the Boulder Canyon reservoir and from the reservoirs that will lie back of the Bridge Canyon, Bullshead and Parker dames, if and when constructed.
[table]
The three following tables, which contain data taken from the various reports on Colorado River matters but mostly from a joint report by Messrs. Jacobs and Stevens, consulting engineers, and a report of R.J. Tipton, consultinhg engineer, entitled, "Report on Colorado River and Allied Matters," are presented to indicate what may become of the 9,500,000 acre-feet given in the foregoing table as the average annual flow past Boulder Dam under ultimate conditions of depletion. These tables are not intended to indicate any conclusions or opinions of the writer. In every case they show the maximum quantities proposed.
[tables]